Kon-El and sunstone

[NotSuper]

In the Busiek/Johns run on the Superman titles, Luthor mentions that Kon-El used sunstone against his "duplicate"--Superboy-Prime. Now, in their fight I don't recall seeing Kon use any crystal against Prime. And it's not like he can use it now since he's dead.

Am I missing something here or did DC forget to add this part to the fight?

[NotSuper]

Also, isn't sunstone only supposed to store information? How could Kon use that against Prime?

[Yoda]

Assuming the Sun Stone is the portion of crystal Luthor gave him, he used it to find Superboy-Prime. That could be what Luthor's talking about.

[NotSuper]

Assuming the Sun Stone is the portion of crystal Luthor gave him, he used it to find Superboy-Prime. That could be what Luthor's talking about.
Ah, I see. Thanks.